Various dibenzo[b,f][1,2,4]triazolo[4,3-d][1,4]-oxazepin and thiazepin-3(2H)-ones as well as such compounds substituted in the 2-position by an alkyl, alkylamino, alkylaminoalkyl, pyrrolidino, piperidino or N-methyl piperazino group are taught to possess useful tranquilizing and antidepressant activity in U.S. Pat. Nos. 3,853,881 and 3,853,904 to Szmuszkovicz.